Pleistocene separation of mitochondrial lineages of Mytilus spp. mussels from Northern and Southern Hemispheres and strong genetic differentiation among southern populations

摘要: Smooth-shelled mussels, Mytilus spp., have an antitropical distribution. In the Northern Hemisphere, M. edulis complex of species is composed three genetically well delineated taxa: edulis, galloprovincialis and trossulus. Southern morphological characters, allozymes intron length polymorphisms suggest that spp. populations from South America Kerguelen Islands are related to those Australasia galloprovincialis. On other hand, a phylogeny 16S rDNA mitochondrial locus demonstrates clear distinctiveness southern mussels suggests they Mediterranean Here, we analysed faster-evolving cytochrome oxidase subunit I locus. The divergence between haplotypes two hemispheres was confirmed found predate northern addition, strong genetic structure detected among samples, revealing entities correspond (1) Island, (2) Tasmania, (3) New Zealand. Using trans-Arctic interchange as molecular clock calibration, estimated time since be 0.5 million years (MY) 1.3 MY (average 0.84 MY). contrasting patterns observed for nuclear organelle genomes suggested alternative, scenarios: trans-equatorial migrations existence differential barriers gene flow, or single migration view composition genome biased by taxonomic preconception.